When a mobile phone is turned on, a device controller first switches a subscriber identity module (SIM) in contact with a SIM controller. The SIM controller, which is a sub-controller for the device controller, performs necessary data transfer with the subscriber identity module for authentication and wireless communication. After the data transfer, the SIM is disconnected from the SIM controller and switched in contact with a radio modem for wireless communication.
First mobile phones had one subscriber identity module card. Since then the number of SIM cards has increased. A present mobile phone may have dual or triple SIM cards. Although a number of SIMs could bring many advantages, dealing with a plurality of SIMs isn't simple. The switching between the at least one SIM and the SIM controller consumes time and increases complexity. Hence, there is a need for better solutions.